It is not a crime. It is only a civil violation. Maybe a distinction without a difference.
In many cases, it is possible to structure things like this so it would not be a labor law violation, but if the only difference between regular employees and this guy was that he was paid on a 1099, it is almost certainly one or more labor law violations of some sort.
The irs can and has criminally prosecuted for 1099's used to defraud
My wife is a cpa who specializes in taxes/audits
Illegal scams can lead to significant penalties and interest and possible criminal prosecution. IRS Criminal Investigation works closely with the Department of Justice (DOJ) to shutdown scams and prosecute the criminals behind them.